Recently, less invasive surgeries such as treatments using catheters have been performed. The treatments using catheters include a coil embolization treatment. The coil embolization treatment is a treatment using a coil to place it in a cerebral aneurysm to embolize it to prevent the cerebral aneurysm, which is a cause of subarachnoidal hemorrhage, from rupture. FIG. 13 schematically shows a medical instrument used in a coil embolization treatment.
FIG. 13 shows a medical instrument 100. In this instrument, a coil 101 formed of platinum is used for embolizing a cerebral aneurysm 133. Coil 101 is connected to a tip of a delivery wire 104. Delivery wire 104 is inserted in a catheter, which includes a parent catheter 103 serving as an outer tube and a child catheter 102 serving as an inner tube to provide a double lumen catheter. Child catheter 102 is hollowed and delivery wire 104 is inserted into the hollowed portion of child catheter 102. Delivery wire 104 is inserted in a Y connector 121, and child catheter 102 is inserted in a Y connector 111.
Delivery wire 104 is manipulated by a doctor at a holding portion 106 located in a vicinity of an entrance of Y connector 121. Catheter 102 is manipulated by another doctor at a holding portion 105 located in a vicinity of an entrance of Y connector 111. In other words, two doctors manipulate delivery wire 104 and child catheter 102, respectively, in the vicinities of the entrances of Y connectors 111 and 121.
Y connector 111, 121 has three connection ports. One is a port for connecting a catheter. Another is a port for receiving a catheter, a delivery wire or a similar linear body. The other is ports 112, 122 for introducing physiological saline, agents and the like.
Parent catheter 103 is inserted into a human body 131 through a blood vessel 132 and has a tip having reached a vicinity of cerebral aneurysm 133. Child catheter 102 is inserted in parent catheter 103, and advanced through a tip of parent catheter 103 into cerebral aneurysm 133. Child catheter 102 reaches cerebral aneurysm 133 and from child catheter 102 coil 101, which is thin and soft, is pushed out and thus embolizes cerebral aneurysm 133. Cerebral aneurysm 133 is thus prevented from rupture.
FIG. 14 is a flowchart of a procedure of a coil embolization treatment. The coil embolization treatment is generally performed in a procedure shown in FIG. 14. Initially in step (S10) the double lumen structure of two catheters (parent catheter 103 and child catheter 102) and a guide wire used to guide the catheters to a target site are inserted into a femoral artery. Child catheter 102 is inserted in parent catheter 103 and the guide wire is inserted in child catheter 102. Then in step (S20) child catheter 102 has a tip guided by the guide wire and thus placed in cerebral aneurysm 133.
Then in step (S30) the guide wire is pulled out of child catheter 102. Then, step (S40) is performed to insert delivery wire 104 having a tip with platinum coil 101 attached thereto in place of the guide wire into child catheter 102.
Then step (S50) is performed to place coil 101 in cerebral aneurysm 133. Then step (S60) is performed to connect an electrode to delivery wire 104 and also connect an electrode to a needle previously stuck in human body 131 and thereafter pass a current between delivery wire 104 and human body 131 via the electrodes. Coil 101 and delivery wire 104 are connected by an electrolytic material, and accordingly, the passed current separates coil 101 and delivery wire 104 and as a result coil 101 is placed in cerebral aneurysm 133.
Then, step (S70) is performed to draw delivery wire 104 out of child catheter 102. Then, step (S80) is performed to determine whether coil 101 closely fills cerebral aneurysm 133. If not, the control returns to step (S40) to insert into child catheter 102 delivery wire 104 having another coil 101 attached thereto. Steps (S40) to (S70) are repeated until coil 101 closely fills cerebral aneurysm 133.
If it is determined that coil 101 has closely filled cerebral aneurysm 133, then, step (S90) is performed to draw parent catheter 103 and child catheter 102 out of human body 131. The treatment of cerebral aneurysm 133 by coil embolization is thus completed.
FIG. 15 schematically shows a catheter operation performed to place a coil in a cerebral aneurysm. As shown in FIG. 15(a), when a coil 101 connected to the tip of delivery wire 104 is placed in cerebral aneurysm 133 to embolize cerebral aneurysm 133, coil 101 may unevenly be distributed in cerebral aneurysm 133 and have an increased density in a vicinity of the tip of child catheter 102. When child catheter 102 has its tip in an area 134 having the coil densely, inserting coil 101 into cerebral aneurysm 133 is accompanied by increased resistance.
If delivery wire 104 is further advanced into blood vessel 132 with the increased insertion resistance, cerebral aneurysm 133, which renders the blood vessel's wall thin and fragile, may rupture. Accordingly, when that coil 101 is inserted with large insertion resistance is detected, the doctor who is manipulating delivery wire 104 temporarily stops inserting delivery wire 104.
Furthermore, the doctor who manipulates child catheter 102 retracts child catheter 102. More specifically, as shown in FIG. 15(b), the doctor who manipulates child catheter 102 moves child catheter 102 in a direction DR1 to draw the catheter out of blood vessel 132. Thereafter, the doctor who manipulates child catheter 102 again advances child catheter 102. More specifically, the doctor who manipulates child catheter 102 moves child catheter 102 in a direction DR2 to insert the catheter into blood vessel 132, as shown in FIG. 15(c),
Child catheter 102 thus once retracted and again advanced has its tip repositioned and thus moved in cerebral aneurysm 133 to an area 135 having the coil less densely. When child catheter 102 has its tip with coil 101 around it less densely, coil 101 can be inserted into cerebral aneurysm 133 with smaller insertion resistance. In that condition, the doctor who manipulates delivery wire 104 resumes inserting delivery wire 104, i.e., coil 101 into cerebral aneurysm 133.
Thus a catheter treatment requires delicate control in manipulating catheters 102 and 103, delivery wire 104 and the like. Accordingly, it requires a skilled operator. Accordingly, to perform a catheter treatment with catheters 102 and 103, delivery wire 104 and the like improved in operability, some master-slave drive devices have been proposed (see Japanese Patent Laying-open Nos. 2000-042116 and 2001-157662 (Patent Documents 1 and 2, respectively, for example).